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MODELLING OF HIGH POWER THYRISTORS UP TO SURGE LEVELS FOR OBTAINING V-I CHARACTERISTICS
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| Author(s) |
. Y. A. Shammas; J. K. Chester |
| Abstract |
There are situations where a knowledge of the isothermal V-I characteristics of high power thyristors up to high current levels can be very useful. Obtaining such characteristics is immediately made difficult by the time taken for a large device to become fully conducting (the spreading time) and the need to prevent it from heating up. If the thyristor is not fully conducting the characteristics are meaningless; and if the device heats up the characteristics are no longer isothermal. A technique is presented using a fast high current (characteristic tracing) pulse superimposed on a low level, longer duration spreading pulse. The rate of rise of the fast pulse has to be optimised because irreducible self and mutual inductances in the voltage measurement gives errors which increase with di/dt and become important before the heating effect has become negligible. Careful attention to experimental detail has been coupled with numerical processing of the raw data to eliminate residual heating and di/dt effects. The method has been used in a supporting role with other experimental and numerical processing techniques for deriving high accuracy coupled electrical and thermal models of power thyristors for use in HVDC and SVC type applications. |
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| Filename: | Unnamed file |
| Filesize: | 1.456 MB |
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| Type |
Members Only |
| Date |
Last modified 2019-08-15 by System |
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